Fertilisers are chemical compounds used to replenish minerals in crop fields. Three important elements need to be replenished in crop field as they are used up by repeated cultivation of the land. Fertiliser provide these elements like nitrogen, phophorous and potassium . The NPK fertilisers comprise nitrophoshate with potash in varying proportions. The dosage varies according to the crop, soil, season and other climatic conditions. They increase the nutrient content of the soil.